Infections of the digestive tract

Infections from harmful viruses, bacteria, or parasites sometimes lead to chronic diarrhea. Children may become infected through contaminated water, beverages, or food; or through person-to-person contact. After an infection, some children have problems digesting carbohydrates such as lactose or proteins in foods such as milk, milk products, or soy. These problems can cause prolonged diarrhea—often for up to 6 weeks—after an infection. Also, some bacterial and parasitic infections that cause diarrhea do not go away quickly without treatment.

Celiac disease

Celiac disease is a digestive disorder that damages the small intestine. The disease is triggered by eating foods containing gluten. Gluten is a protein found naturally in wheat, barley, and rye. Gluten is common in foods such as bread, pasta, cookies, and cakes. Celiac disease can cause chronic diarrhea in children of any age.

Functional GI disorders

In functional GI disorders, symptoms are caused by changes in how the digestive tract works. Children with a functional GI disorder have frequent symptoms, yet the digestive tract does not become damaged. Functional GI disorders are not diseases; they are groups of symptoms that occur together.

Two functional GI disorders that cause chronic diarrhea in children are toddler’s diarrhea and irritable bowel syndrome (IBS).

Toddler’s diarrhea
Toddler’s diarrhea—also called functional diarrhea, or chronic nonspecific diarrhea of childhood—is a common cause of chronic diarrhea in toddlers (ages 1 to 3), and preschool-age children (ages 3 to 5). Children with toddler’s diarrhea pass four or more watery or loose stools a day and do not have any other symptoms. They typically are growing well, gaining weight, and are healthy.

Toddler’s diarrhea develops between the ages of 6 months and 3 years, and it usually goes away on its own by the time children begin grade school. Researchers think that drinking too many sugar-sweetened beverages, especially those high in high-fructose corn syrup and sorbitol, may cause toddler’s diarrhea.

IBS
The most common symptoms of IBS are abdominal pain, discomfort, or cramping; along with diarrhea, constipation, or both. The pain or discomfort of IBS typically gets better with the passage of stool or gas. IBS does not cause symptoms such as weight loss, vomiting, or blood in the stool.

IBS is a common cause of chronic diarrhea in grade school-age children and adolescents. Doctors rarely diagnose IBS in younger children because younger children are not able to report symptoms of IBS such as abdominal pain or discomfort.

Food allergies and intolerances

Food allergies
Milk, milk products, and soy allergies are the most common food allergies that affect the digestive tract in children. Food allergies usually appear in the first year of life. Many children outgrow allergies to milk, milk-products, and soy by age 3. Allergies to other foods such as cereal grains, eggs, and seafood may also affect the digestive tract in children.

Lactose intoleranceLactose intolerance is a common condition that may cause diarrhea after eating foods or drinking beverages that contain milk or milk products. Low levels of lactase—the enzyme that helps digest lactose—or lactase deficiency, and malabsorption of lactose cause lactose intolerance.

The most common type of lactase deficiency in children develops over time, beginning after about age 2, when a child’s body begins to produce less lactase. Children who have lactase deficiency may not experience symptoms of lactose intolerance until they become older teenagers or adults.

Infants—newborns to age 1—rarely have lactose intolerance at birth. However, premature infants may experience lactose intolerance for a short time after birth. People sometimes mistake milk allergy, which can cause diarrhea in infants, for lactose intolerance.

Fructose intolerance
Fructose intolerance is a condition that may cause diarrhea after eating foods or drinking beverages that contain fructose, a sugar found in fruits, fruit juices, and honey. Fructose is added to many foods and soft drinks as a sweetener called high-fructose corn syrup. Fructose malabsorption causes fructose intolerance. The amount of fructose that a child’s body can absorb varies. A child’s ability to absorb fructose increases with age. Some children may be able to tolerate more fructose as they get older.

Sucrose intolerance
Sucrose intolerance is a condition that may cause diarrhea after eating foods or drinking beverages that contain sucrose, also known as table sugar or white sugar. Sucrose malabsorption causes sucrose intolerance. Children who are sucrose intolerant lack the enzyme that helps digest sucrose. Most children with sucrose intolerance are better able to tolerate sucrose as they get older.

Inflammatory bowel disease (IBD)

The two main types of IBD are Crohn’s disease and ulcerative colitis. These disorders can affect children at any age. However, they commonly begin in the grade school years or in adolescence.

Small intestinal bacterial overgrowth (SIBO)

SIBO is an increase in the number of bacteria or a change in the type of bacteria in your small intestine. SIBO is often related to diseases that damage the digestive system such as Crohn’s disease.

This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases
(NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings
through its clearinghouses and education programs to increase knowledge and understanding about health and
disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully
reviewed by NIDDK scientists and other experts.

The NIDDK would like to thank:
Mark Donowitz, M.D., Johns Hopkins University School of Medicine

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